2005 Sienna ventilation never off

This may have been asked and answered, here, but I'm never sure what, exactly, to search for.

I bought a used 2005 Sienna XLE in October 2009. Is it normal that, even when my heat/ac fan is "off," it still blows air? If it was last set warm, it blows warm. If it was last set cool, it blows cool. But it's never OFF, completely. It only blows slightly, even if I last had it set high, so I'm getting the impression that Toyota assumed you'd never want it completely off (a dumb assumption, if they did) - but I *do* want it off. Am I missing some mystery control that shuts this all the way off?

It's normal operation, you may be used to other vehicles where the outside air damper closes when the fan shuts off and there is no separate Recirc switch to close off outside air. like the Toyota version as I can shut off the fan on the highway if temps are moderate and just let the air flow in thru the vents and can still modulate the discharge temperature.

In recirculate mode there is very little cabin air "outflow" and so the cabin humidity will continually rise as a result of human metabolism, breathing, perspiration, etc, the more bodies the higher the Rh will climb.

Regretably this all relates to dewpoint and mother nature is mostly in charge of that parameter. So it's a good idea to NEVER use recirculate when the primary HVAC mode is for heating, keeping the passenger cabin warmed.

The new 2010 RX350's automatic climate control will not only prevent you from using recirculate "improperly" but will automatically switch the system into combined floor/windshield air outflow depending on outside climatic conditions. That will tend to keep the interior surface of the windshield warmed above dewpoint even with COLD airflow impinging on the exterior surface.

Sorry, that just isn't believable these days when as a safety measure systems will not remain in recirculate mode with the A/C off.

And...

A manual HVAC that has a servomotor that automatically closes the fresh air inflow path when the blower is turned off.

"Does NOT compute..!!""

"..would shutoff the outside air damper.."

The MANUAL system outside air damper, typically, has two positions, FRESH and RECIRCULATE. It might automatically move from recirculate to fresh if the blower is turned off, and more likely so, MUCH more likely so if the A/C is turned off. But it would be patently UNSAFE for it to completely close off the incoming fresh air flow.